Mandrel with means for clamping and spreading tubes



May 31, 1949.

F. A. GRUETJEN 2,471,485

MANDREL WITH MEANS FOR CLAMPING AND SPREADING TUBES Filed Oct. 23. 1943 3 Sheets-Sheet 1 ATTORNEY May 31, 1949.

MANDBEL WITH MEANS FOR CLAMPING AND SPREADING TUBES Filed Oct. 23, 1943 F. A. GRUETJEN 86 3 Shets-Sheet 2 5 97 f I 32 a5 I I j::;. mull (D I: 6 36 52 9a 25 a 26 29 I I. .II In! I'" Z4 Z5 ml I l 6 7 III l 25 26 I l l frederzkk A. Gnu {fen INVENTOR.

ATTORNEY.

F. A. GRUETJEN MANDREL WITH MEANS FOR CLAMPING AND SPREADING TUBES Filed Oct. 23, 1943 3 Sheets-Sheet 3 m r. J Mm Q m mm m @MM (m... A Q Q 7m QM Q Patented May 31. 194

MANDREL WITH MEANS FOR CLAMPING AND SPREADING TUBES Frederick A. Gruetjen, Milwaukee, Wis., asslgnor to A. 0. Smith Corporation, Milwaukee, Wis., a corporation of New York Application October 23, 1943, Serial No. 507,365

This invention relates to forming apparatus adapted particularly to the spreading of a tubular member in the direction of its diameter, as in the Figure 1 is a side elevation of the apparatus 7 with the base sectioned and showing a propeller tip in place for forming and partially broken away to show the spreading mandrels;

Fig. 2 is an end elevation of the apparatus;

Fig. 3 is a top plan view of the apparatus;

Fig. 4 is an enlarged horizontal section taken on line 4-4 of Fig. 1;

Fig. 5 is a view similar to Fig. 4 showing the mandrels in their extended positions;

Fig. 6 is a view similar to Figure 1 showing the mandrels in extended positions; and

Fig. 7 is a view similar to Figure 1 with the clamping means released and the mandrels retracted for loading the blank.

The apparatus comprises a table top i having a central opening 2 therethrough, and corner legs 3. A plate 6- is mounted on the table top and carries a frame 5 lying in the opening 2 for supporting the operating mechanism of the apparatus.

The spreading mandrels S and l are disposed vertically back-to-back and have their outer faces tapered and curved to substantially fit the wall of a tapered and bilged tubular tip section B. One mandrel 5 is secured to one end of frame 5 by bolts 9 while the other mandrel l is secured to a movable depending yoke It by bolts H.

Wear plates l2 secured in the frame 5 on either sid of yoke I ll and having curved shoulders 53 matching similar shoulders on the yoke serve to support the yoke so as to maintain the two mandrels 6 and l at the same height. A washer l4 encircles the upper small ends of the mandrels to hold them in alignment. The frame 5 provides a longitudinal slot in which the yoke It operates to spread the mandrels apart at the lower end.

The operation of the movable mandrel l is 8 Claims. (Cl. 153-39) 2 obtained by the air cylinder pivoted to a bracket IS on the legs 3 at one end of the table, andhaving its piston rod l'l connected to the lower end of yoke III by a clevis ll. An adjustable stop IQ is threaded through yoke I 0 to engage a depending lug on table top I and determine the movement of mandrel 1 toward mandrel 6. Similarly, an'adjustable stop 2| is threaded through a depending lug 22 near the end of top I to be engaged by yoke l0 and determine its outward spreading movement which separates the lower ends of mandrels 6 and 1.

In operation, while the'mandrels 6 and l are closed together a tapered tip section 8 is slipped onto them over the top end and then the mandrels are spread apart at the bottom by operation of air cylinder l5 to spread the'blank from a circular section to an oblong section. Operation of the cylinder IE to move its piston in the opposite direction returns the mandrel 'l to vertical position where the blank 8 can be readily removed vertically from the mandrels and a succeeding blank applied. In operation the mandrels 6 and l pivot or rock upon one another at their contacting upper ends, and the upper end .of the blank is spread only a slight amount depending upon its location relative to the pivotal points involved.

Since the tip section of a propeller blade is tapered and bilged in diameter, it is sometimes found that there is a tendency for the blank to rise vertically on' the mandrels during spreading. In addition to this, the blank is twisted to correspond with the final blade twist, and there is a tendency forthe leading and trailing edges to tip sideways when the blank is spread. To prevent this, the apparatus has a pair of spring pressed holding bars 23 and 24.

Holding bar 23 is pivoted. to frame 5 and extends upwardly adjacent the-fixed mandrel 6 with three holding yokes or clamps 25 vertically spaced therealong to engage the outside of the leading edge 26 of blank 8 and hold the blank on the mandrel. Similarly, holding bar 24 is pivoted to a bracket 21 on yoke l0 and extends upwardly adjacent th movable mandrel l with three holding yokes or clamps 28 vertically spaced therealong to engage the outside of the trailing edge 29 of blank 8 and hold the blank on the mandrel.

Side posts 30 and 3| are provided extending upwardly from. the respective ends of plate 4, and

carry lateral brackets 32 for supporting springs 38 for biasing bars 23 and- 24 toward the blank.

For the purpose of separating bars 23 and 2d at the top for quick loading and unloading of blanks to be operated upon, a double bell crank hand lever 34 is pivoted to the upper end of post 30. Theupper arm 35 or lever 34 is connected by a link 36 to the upper end of bar 23, while the' As illustrated in Figure 1, when the lever 34 is raised to horizontal position, the bars 23 and 24 are brought together at the top and held so by spring assemblies 33. Fig. 6 shows the position of the parts with lever 34 in raised position and the mandrels spread apart. When the lever 34 is lowered from the position shown in Fig. 6, link 36 pulls bar 23 away from the blank and link 38 pushes bar 24 away from it, leaving the blank free to be removed. As shown in Fig. '7 the apparatus is in position for loading the blank with the mandrels retracted and lever 34 lowered to hold the clamps open. Operation of the lever 34 is rapid and does not add materially to the time cycle of operation of the apparatus.

The clamps 25 and 28 confine the leading and trailing edges of the blank and hold the same in place during spreading of the mandrel. The shape and width of the mandrels is such that the sides of the blank immediately adjacent the leading and trailing edges quickly engage and form .upon the mandrel surfaces, and the intermediate sides of the blank are free to stretch and flatten.

The invention may have various embodiments within the scope of the claims.

, I claim:- Y

1. In an apparatus for spreading metal articles of substantially circular section to an oblong sectionat one end, a pair of mandrels disposed back-to-back and adapted to pivot relative to one another at one end and move radially out-' wardly relative to one another at'theother end, a fixed support for one of said mandrels at the outwardly movable end, a movable support for the other of said mandrels at the outwardly movable end, power means for operating said movable support to separate said mandrels and effect spreading of the article thereon, a clamp disposed adjacent each mandrel to prevent slippage of the article thereon during spreading, and means for rapidly separating said clamps to provide for unloading and loading of the apparatus.

2. Inan apparatus for spreading metal articlesof substantially circular section to an oblong section at one end, a pair of mandrels disposed back-to-back and adapted to pivot relative to one another at one end and move radially outwardly relative to one another at the other end, a fixed support for one of said mandrels at the outwardly movable end, a movable support for the other of said mandrels at the outwardly movable end, power means for operating said movable support to separate said mandrels and effect spreading of the article thereon, a clamp disposed adjacent each mandrel to prevent slippage of the article thereon during spreading, means for rapidly separating said clamps to provide for unloading and loading of the apparatus, and means normally biasing said clamps into engagement with the article being operated upon.

3. In apparatus of the class described, a pair of mandrels adapted to receive a tubular metal blank, relatively movable supports for said mandrels, aholding barv for each mandrel pivoted at one end to each of said supports and having (clampin'gme'ans for engaging a blank along sub:-

stantially the length thereof 'to clamp the blank to the respective mandrels, and means for securing said holding bars in clamping position.

v 4. In apparatus of the class described, a pair of mandrels, adapted to receive, a tubular metal blank, relatively movable supports for said mandrels, a. holding bar for, each. mari drel. pivoted at one end-to each of said supports-and having clamping means for engaging a blank and clamping the same-to the respective mandrels, means for securing said holding bars in clamping position, and means for separating the free ends of said holding bars to provide for loading a blank upon said mandrels.

5. In apparatus of the class described, a pair of mandrels adapted to receive a tubular metal blank, relatively movable supports for said mandrels, a holding bar for each mandrel pivoted at one end to each of said supports and having clamping means for engaging a blank and clamping the same to the respective mandrels, and a lever linked to the free ends ofsaid holding bars to open and close the same upon the-blank.

6. In an apparatus for spreading metal articles of substantial length and substantlallycircular section to an oblong section, a support, a pair of mandrels mounted on said support and disposed back-to-back and adapted to receive said article, said mandrels engaging and rocking on each other at one end and being adapted to move radially outwardly relative to each other at the other end, means securing said mandrels together atthe engaging ends thereof to hold them in alignment'duringspreading, and motor operated power means mounted on said support connected to one flotsaid mandrels'at said outwardly movable end to rock. the same upon the other mandrel at the opposite secured end and effect spreading of said article encircling the same.

7. In an apparatus for spreading metal articles of substantial length and substantially circular section to an oblong section, a support, a pair of mandrels mounted on said support and disposed back to back and adapted toreceive said article, said mandrels engaging and rocking on each other at 'one end and being adapted to move radially outwardly relative to each other at the other end, means securing said mandrels together at the engaging ends thereof to hold them in alignment during spreading, motor operated power means mounted on said support, and connected to one of said mandrels at said ,outwardly movable end to rock the same upon the other mandrel at the opposite secured, end and effect spreading of said article encircling the same, and a resiliently. backed clamp engaging mandrels, means securing said mandrels together at their engaginginner ends to hold them in aligmnent during spreading, a hydraulic 'cylinder and piston, rod. pivoted jtojthe outerqend of the movable mandrel and to said frame to Y pivotthe movable mandrel onthe fixe mandrelat the inner end thereoi' andi'eiiect eparation I bf the mandrels and "spreading of the article en- 7 5 circling the same, a resiliently backed holding bar for each mandrel-pivoted at one end to said frame. and a. plurality o1. clamps on each bar for engaging the article and clamping the same to the respective mandrels to prevent slippase of 5 the article thereon during spreading. I

FREDERICK A. GRUETJEN.

REFERENCES CITED The ,following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 30,535 Mack Oct. 30, 1860 s 220,996 Singer Oct. 28, 1879 Number Number Germany Jan. 2, 1922 

